Question

tìm x biết: |x² - 2x| = x

Answer 1

\(\left|x^2-2x\right|=x\)

\(\Leftrightarrow x^2-2x=\pm x\)

\(\Leftrightarrow\left[{}\begin{matrix}x^2-2x=x\\x^2-2x=-x\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x^2-2x-x=0\\x^2-2x+x=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x^2-3x=0\\x^2-x=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x\left(x-3\right)=0\\x\left(x-1\right)=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x-3=0\\x=0\\x-1=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=3\\x=1\end{matrix}\right.\)

Vậy...........